Compensatory growth response of rainbow trout Oncorhynchus mykiss Walbaum following short starvation periods

Abstract: This sixty-day study was performed to determine the effects of short-term starvation and refeeding cycles on growth, feeding performances and body composition of rainbow trout ( Oncorhynchus mykiss ). Three hundred trout fi ngerlings with an average initial weight of 17.5±0.06 g were randomly distributed in 15 circular fi berglass tanks. The fi sh were exposed to 5 different feeding regimes; control: continuously fed twice daily to apparent satiation; T 1 : starved for 1 day and re-fed for 2 days; T 2 : starved for 1 day and re-fed for 4 days; T 3 : starved for 3 days and re-fed for 12 days; T 4 : starved for 4 days and re-fed for 16 days. At the end of the experiment, growth performance, feed utilization, whole body ash and moisture contents were not signifi cantly ( P >0.05) different among the treatments. However, whole body protein content in T3 was signifi cantly higher than other treatments ( P <0.05). A signifi cant difference in whole body fat content was observed between T3 and the control group at the end of the experiment ( P <0.05). In conclusion this experiment suggests that feeding schedules involving starvation (1–4 days) and re-feeding cycles are a promising feed management tool for rainbow trout culture.

Keyword : Oncorhynchus mykiss ; compensatory growth; growth performance; body composition